The category "<mount_dismount_command>" can be expressed as follows:

<mount_dismount_command>

<intrans_mount_dismount_verb-located> <location_mod>

<intrans_mount_dismount_verb-not_located>

<trans_mount_dismount_verb-located> <other_unit> <location_mod>

<trans_mount_dismount_verb-not_located> <other_unit>